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United States Patent |
5,180,856
|
Stehr
,   et al.
|
January 19, 1993
|
Polyethers, their production and use
Abstract
New polyethers based on tetrahydrofuran, with good lubricant properties.
The invention concerns polyethers produced by copolymerizing
tetrahydrofuran and glycidyl ether in the presence of alkanols. The new
polyethers are useful as lubricants.
Inventors:
|
Stehr; Michael (Gelsenkirchen, DE);
Voges; Heinz-Werner (Dorsten, DE)
|
Assignee:
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Huels Aktiengesellschaft (Marl, DE)
|
Appl. No.:
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745979 |
Filed:
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August 12, 1991 |
Foreign Application Priority Data
Current U.S. Class: |
568/617; 568/606 |
Intern'l Class: |
C07C 043/11 |
Field of Search: |
568/617,606
|
References Cited
U.S. Patent Documents
4481123 | Nov., 1984 | Hentschel et al.
| |
Other References
Il'chenko et al. Translation from Doklady Akad Nauk SSSR vol. 192, No. 5
(1071-1076) pp. (441-444) 1970.
Il'chenko et al. C.A. 73 88253a (1970).
|
Primary Examiner: Mars; Howard T.
Attorney, Agent or Firm: Oblon, Spivak, McClelland, Maier & Neustadt
Parent Case Text
This application is a continuation of application Ser. No. 07/471,388,
filed on Jan. 29, 1990, now abandoned.
Claims
What is claimed is:
1. A polyether obtained by the process consisting essentially of:
polymerizing tetrahydrofuran with a glycidyl ether having the formula:
##STR2##
in the presence of at least one alcohol having the formula R.sup.2 --OH,
wherein R.sup.1 is an alkyl group with 3-20 carbon atoms, and R.sup.2 is
an alkyl group with 8-24 carbon atoms, a cycloalkyl group with 6-12 carbon
atoms in the ring, a hydroxyalkyl group with 4-36 carbon atoms, or a
cycloalkanol group with 6-15 carbon atoms in the ring to form a polymer,
said polymer having an osmotic molecular weight of 870-1920,
wherein the molar ratio of said alkanol to tetrahydrofuran and glycidyl
ether is about 1:5 to 1:200, the molar ratio of tetrahydrofuran to
glycidyl ether is about 1:6 to 15:1, and wherein the polymerization is
carried out at a temperature of from about -10.degree. C. to about
100.degree. C. in the presence of 0.01-5 weight % of a Lewis acid
catalyst.
2. The polyether of claim 1, wherein the molar ratio of tetrahydrofuran and
glycidyl ether used is 1:3 to 8:1.
3. The polyether of claim 1, wherein the molar ratio of tetrahydrofuran and
glycidyl ether used is 1:1 to 5:1.
4. The polyether of claim 1, wherein R.sup.1 is an alkyl group with 6-20
carbon atoms.
5. The polyether of claim 1, wherein R.sup.1 is an alkyl group with 10-20
carbon atoms.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention describes the preparation of new polyethers which can
be used as lubricants, particularly as gear lubricants.
2. Discussion of the Background
The use of polyethers as lubricants or as an additive in conventional
lubricant oils based on mineral oil is known. The state of the art as well
as the demands generally made on such lubricants are particularly
described in EP-PS 0 064 236. Suitable values for evaluating the quality
of a lubricant oil are the viscosity index VI and the friction coefficient
determined using a Reichert wear scale. High-quality lubricants are
characterized by a high viscosity index, i.e. extensive temperature
independence of the viscosity, as well as low friction coefficients.
Additional criteria are compatibility with mineral oil, hydrophobic
properties, low pour point and high resistance to heat.
According to EP-PS 0 064 236, polyethers which can be used as lubricants
are obtained by copolymerization of a tetrahydrofuran with terminal
oxiranes in the presence of monofunctional or bifunctional hydroxy
compounds. The oxiranes used are long-chain 1,2-epoxyalkanes with 8-26
carbon atoms, which are used either alone or in a mixture with lower
alkylene oxide components, such as ethylene, propylene and/or butylene
oxide, as comonomers. These long-chain 1,2-epoxyalkanes can be replaced
with glycidyl esters of neoalkane carboxylic acid to a certain extent (see
Example 7). However, this measure results in a polyether with a
significantly worsened viscosity/temperature behavior, as the comparison
with a polyether having a similar molecular weight but not containing any
glycidyl ester components shows (see Example 1). Glycidyl esters therefore
do not represent an adequate substitute for 1,2-epoxyalkanes. The use of
the latter group of compounds therefore appears to be essential for the
synthesis of polyethers which satisfy the property profile required by
EP-PS 0 064 236.
A need continues to exist for new polyethers which demonstrate good
lubricant properties.
SUMMARY OF THE INVENTION
One object of the present invention is to provide a high-quality polyether
lubricant oil.
This and other objects which will become apparent from the following
specification have been achieved by the present polyethers which are
obtained by polymerization of tetrahydrofuran with glycidyl ethers.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
It has been discovered that high-quality polyether lubricant oils are
obtained if tetrahydrofuran is copolymerized with glycidyl ethers having
the formula
##STR1##
where R.sup.1 is alkyl in the presence of alkanols with the general
formula R.sup.2 OH, where R.sup.2 is an alkyl or hydroxyalkyl group.
In the present process, polyethers are obtained by polymerization of
tetrahydrofuran with the glycidyl ethers having the formula shown above,
in the presence of alkanols having the formula R.sup.2 --OH, where R.sup.1
represents alkyl groups with 3-20 carbon atoms, and R.sup.2 represents
alkyl groups with 8-24 carbon atoms, cycloalkyl groups with 6-12 carbon
atoms in the ring, or hydroxyalkyl groups with 4-36 carbon atoms, as well
as cycloalkanol groups with 6-15 carbon atoms in the ring.
Copolymerization of tetrahydrofuran and glycidyl ethers can be carried out
by known methods (Angew. Chemi 72, 927-934 (1960)), by allowing the
components to react in the presence of an alkanol, which acts as a
molecular weight regulator under catalysis with Lewis acids, such as e.g.
aluminum chloride, ferric chloride, tin (IV) chloride, titanium
tetrachloride, antimony pentachloride and boron trifluoride, for example,
as well as adducts thereof. A preferred Lewis acid is boron trifluoride
diethyl etherate.
In the process according to the invention, the Lewis acid used as a
polymerization initiator is used in an amount of about 0.01 to 5% by
weight, relative to the entire reaction mixture.
The process according to the invention is generally carried out in a
temperature range of from about -10.degree. C. to about 100.degree. C.,
preferably between 0.degree. and 80.degree. C., and especially preferably
between 20.degree. and 60.degree. C.
The process of the invention can be carried out at normal pressure or at
higher pressures, preferably at normal pressure.
Typical glycidyl ethers used according to the invention are, e.g. n-butyl,
n-hexyl, n-octyl, n-decyl, n-dodecyl, and n-tetradecyl glycidyl ether as
well as 2-ethylhexyl, 2-propylheptyl and iso-tridecyl glycidyl ether.
Preferred alkanols are 1-octanol, 1-nonanol, 1-decanol, 1-dodecanol,
1-tetradecanol, 1-hexadecanol, 1-octadecanol, 1,6-cyclohexane dimethanol,
cyclooctanol, cyclooctanediol, cyclooctane dimethanol and cyclododecanol.
Glycidyl ethers are easily prepared from materials that are readily
technically available. They are obtained, for example, by conversion of
epichlorhydrin with alkanols to form 3-alkoxy-1-chlor-2-propanolene and
subsequent intramolecular ring-closure in the presence of an alkali metal
hydroxide. However, the production method for the glycidyl ethers used is
not limited and includes any known method for preparing these ethers.
The lubricant properties of the polyethers according to the invention can
be determined within wide limits by an advance selection of a certain
glycidyl ether and an alkanol used as a molecular weight regulator, as
well as by variation of the molar ratios of alkanol, tetrahydrofuran and
glycidyl ether. The molar ratio of alkanols used to tetrahydrofuran and
glycidyl ether varies, depending on the desired viscosity of the polyether
oil. The viscosity depends on the molecular weight, i.e. the number of
monomer units per polyether molecule and in the present polyethers the
molar ratio is generally from 1:5 to 1:200. Compositions in which the
molar ratio of tetrahydrofuran/glycidyl ether (THF/GE) is 1:6 to 15:1,
preferably 1:3 to 8:1, especially preferably 1:1 to 5:1, are desirable.
Polyether oils with low viscosity are, of course, those in which the
proportion of the molecular weight regulator was selected to be high (e.g.
alkanol:THF:GE is about 1:4:2); polyethers with a high molecular weight,
in other words highly viscous oils, are those in which the proportion of
the molecular weight regulator was selected to be low (e.g. alkanol:THF:GE
is about 1:40:15). By a corresponding selection of the regulator amount,
polyethers with medium viscosity can also be produced.
Corresponding to the variable property profile, polyethers can be
considered for different tribological areas of application: hydraulic
fluids, brake fluids, metal processing fluids, lubricants for compressors
and refrigerators, bearing and gear oils for units under high thermal
stress (e.g. calenders) in the paper, textile and plastics industries.
The polyethers according to the invention can also be used as heat carrier
oils.
It is known that particularly high-quality lubricant oils are obtained by
adding suitable additives, preferably against oxidation, corrosion, wear
and foaming, to polyethers. This also applies to the polyethers according
to the invention. The suitable additives are selected from the very large
number of known compounds and substances which are described in the
literature to improve the oxidation, corrosion, wear and foaming
resistance of synthetic or natural lubricant oils (see D. Klamann,
Schmierstoffe und verwandte Produkte, Verlag Chemie, Weinheim 1982, p. 81
ff).
Other features of the invention will become apparent in the course of the
following descriptions of exemplary embodiments which are given for
illustration of the invention and are not intended to be limiting thereof.
EXAMPLES
Example 1
A mixture of 4 g n-decanol and 20 ml water-free tetrahydrofuran (THF) was
mixed with 2.2 ml BF.sub.3.Et.sub.2 O and stirred for one hour at
45.degree. C. After this time, a mixture of 12 g n-decanol, 180 ml
water-free tetrahydrofuran and 60 g n-butyl glycidyl ether was slowly
dripped in, with the temperature not exceeding 55.degree. C. After the
addition had been completed, the mixture was allowed to continue reacting
for 64 h at room temperature. For processing, the reaction mixture was
mixed with a solution of 3.8 g Na.sub.2 CO.sub.3 (soda) in 20 ml water,
stirred for one hour at room temperature and then the water and substances
with a low boiling point were distilled off at a pot temperature of
100.degree. C. and at normal pressure. The resulting residue was freed
from precipitated solids by filtration or centrifugation. Finally, the oil
was heated to 200.degree. C. for 2 hours at a pressure of 0.05 torr, in
order to remove volatile admixtures.
______________________________________
Yield: 135.0 g
Osmotic molecular weight:
1,220
Elemental analysis: 66.21% C
11.44% H
22.37% O
Kinematic viscosity at
37.8.degree. C. 146.8 mm.sup.2 /s
98.9.degree. C. 24.1 mm.sup.2 /s
Viscosity index: 198
______________________________________
Example 2
A solution of 40 ml water-free THF and 5 g of a mixture of n-dodecanol and
n-tetradecanol (3:1) was mixed with 2.8 ml BF.sub.3.Et.sub.2 O and stirred
for one hour at 45.degree. C. After this time, a mixture of 160 ml
water-free THF, 120 g n-butyl glycidyl ether as well as 16 g of a mixture
of n-dodecanol and n-tetradecanol was slowly dripped in, with the
temperature not exceeding 55.degree. C. The mixture was allowed to
continue reacting for 20 h at room temperature, 4.6 g soda in 30 ml water
was added, and the workup performed as in Example 1.
______________________________________
Yield: 230.4 g
Osmotic molecular weight:
1,490
Elemental analysis: 66.82% C
11.21% H
22.70% O
Kinematic viscosity at
37.8.degree. C. 162.7 mm.sup.2 /s
98.9.degree. C. 32.3 mm.sup.2 /s
Viscosity index: 245
______________________________________
Example 3
A solution of 5 g of a mixture of n-dodecanol and n-tetradecanol (3:1) in
40 ml water-free THF was mixed with 2.0 ml BF.sub.3.Et.sub.2 O and stirred
for one hour at 45.degree. C. After this time, a mixture of 160 ml
water-free THF, 30 g n-butyl glycidyl ether and 16 g C.sub.12 /C.sub.14
alcohol was slowly dripped in, with the temperature not exceeding
55.degree. C. After the addition was complete, the mixture was allowed to
continue reacting for 20 h at room temperature, the reaction mixture was
mixed with 3.3 g soda in 20 ml water, and worked up as in Example 1.
______________________________________
Yield: 100 g
Osmotic molecular weight:
1,070
Elemental analysis: 67.48% C
11.52% H
20.89% O
Kinematic viscosity at
40.degree. C. 93.7 mm.sup.2 /s
100.degree. C. 16.6 mm.sup.2 /s
Viscosity index: 191
______________________________________
Example 4
A solution of 3.1 g of a mixture of n-dodecanol and n-tetradecanol (3:1) in
18 ml water-free THF was mixed with 1.4 ml BF.sub.3.Et.sub.2 O and stirred
for one hour at room temperature. After this time, a solution of 39.5 g
of the alcohol mixture described above and 103 g n-butyl glycidyl ether
was slowly dripped in, so that the temperature did not exceed 55.degree.
C. After the addition was complete, the mixture was stirred for another 22
h at room temperature, then mixed with a solution of 2.3 g soda in 20 ml
water, and worked up as in Example 1.
______________________________________
Yield: 118.6 g
Osmotic molecular weight:
870
Elemental analysis: 67.28% C
11.32% H
21.35% O
Kinematic viscosity at
40.degree. C. 49.3 mm.sup.2 /s
100.degree. C. 9.3 mm.sup.2 /s
Viscosity index: 175
______________________________________
Example 5
A solution of 13.0 g of a mixture of n-hexadecanol and n-octadecanol (1:2)
in 100 ml water-free THF was mixed with 3.2 ml BF.sub.3.Et.sub.2 O and
stirred for one hour at 45.degree. C. After this time, a solution of 95.6
g n-butyl glycidyl ether and 200 ml water-free THF was slowly dripped in,
with the temperature not exceeding 55.degree. C. After the addition was
complete, the mixture was stirred for 68 hours at room temperature, 5.3 g
soda in 30 ml water was added, and workup continued as usual.
______________________________________
Yield: 258.6 g
Osmotic molecular weight:
1,920
Elemental analysis: 66.11% C
11.19% H
22.82% O
Kinematic viscosity at
40.degree. C. 480.2 mm.sup.2 /s
100.degree. C. 82.3 mm.sup.2 /s
Viscosity index: 256
______________________________________
Example 6
1.8 ml boron trifluoride etherate was added to a solution of 10 g decanol
in 25 ml water-free THF. The mixture was stirred for one hour at
45.degree. C. and then, a mixture of 83.0 g n-decyl glycidyl ether and 125
ml water-free THF was slowly dripped in, so that the temperature does not
exceed 55.degree. C. After the addition was complete, the mixture was
allowed to react for another 22 hours at room temperature. For workup, the
reaction mixture was mixed with a solution of 3.0 g soda in 50 ml water,
and further processing took place as in Example 1.
______________________________________
Yield: 145 g
Osmotic molecular weight:
1,650
Elemental analysis: 70.66% C
12.28% H
17.62% O
Kinematic viscosity at
40.degree. C. 173.1 mm.sup.2 /s
100.degree. C. 27.6 mm.sup.2 /s
Viscosity index: 198
______________________________________
Example 7
2.4 ml boron trifluoride etherate was added to a solution of 11.5 g
1,5-cyclooctane dimethanol in 30 ml water-free THF. The mixture was
stirred for one hour at 45.degree. C., and then, a mixture of 65.0 g
n-butyl glycidyl ether and 220 ml water-free THF was slowly dripped in, so
that the temperature does not exceed 55.degree. C. After the addition was
complete, the mixture was allowed to react for another 22 hours at room
temperature. For workup, the reaction mixture was mixed with a solution of
4.0 g Na.sub.2 CO.sub.3 in 90 ml water, and further workup took place as
in Example 1.
______________________________________
Yield: 150.2 g
Osmotic molecular weight:
1,220
Elemental analysis: 66.01% C
11.21% H
23.27% O
Kinematic viscosity at
40.degree. C. 318.3 mm.sup.2 /s
100.degree. C. 42.5 mm.sup.2 /s
Viscosity index: 188
______________________________________
Obviously, numerous modifications and variations of the present invention
are possible in light of the above teachings. It is therefore to be
understood that within the scope of the appended claims, the invention may
be practiced otherwise than as specifically described herein.
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